The investigation of the practicality of zinc radiopharmaceuticals for non-invasive ocular melanoma detection is the primary objective of this proposal. Naturally high levels of zinc found within the uveal tissues and the known association of zinc with melanin combine to form the rationale for the application of zinc compounds. The secondary objective is to understand the function of zinc within ocular tissues and melanoma using as a model of human choroidal melanoma, the Greene melanoma transplanted to the eye of the Golden Hamster. 65Zn and radiopharmaceuticals presently used for melanoma localization will be injected into the animals and the uptake ratio between cancerous and normal ocular tissues measured. The effect on uptake of the chemical complex of zinc, of the site and time of injection, and of the dietary content of natural zinc will be investigated. Natural zinc stores within normal and neoplastic tissue will be measured by atomic absorption analysis methods, in vitro, and X-ray fluorescence, in vivo.